JP6894419B2 - Positive electrode active material for secondary batteries and its manufacturing method - Google Patents

Description

The present invention relates to a positive electrode active material for a secondary battery and a method for producing the same. More specifically, in a lithium composite oxide composed of secondary particles in which primary particles are aggregated, lithium manganese oxidation is performed in the peripheral portion of the primary particles. things present, represents a concentration gradient from the center to the particle surface of the concentration of the lithium manganese oxide is the primary particles, represents a concentration gradient from the particle surface toward the center in the concentration the secondary particles of the lithium manganese oxide, The present invention relates to a lithium composite oxide having a lithium ion transfer path in the primary particles and a method for producing the same.

The lithium secondary battery, which was developed in the early 1990s and has been used so far, is a light and small large-capacity battery, and is in the limelight as a power source for mobile devices. Lithium secondary batteries have a higher operating voltage than conventional batteries such as nickel-hydrogen (Ni-MH), nickel-cadmium (Ni-Cd), and lead sulfate-lead batteries that use an aqueous electrolyte. It has the advantage of significantly higher energy density. In particular, recently, research on a power source for an electric vehicle in which an internal combustion engine and a lithium secondary battery are hybridized has been actively promoted in the United States, Japan, Europe and the like.

The production of large batteries for electric vehicles using lithium secondary batteries has been considered from the viewpoint of energy density, but until now, nickel-metal hydride batteries have been used for electric vehicles in consideration of safety. Lithium secondary batteries have limitations in their application to electric vehicles due to their high price and safety issues. In particular, the _{lithium secondary batteries currently commercialized containing LiCoO 2} or LiNiO ₂ as a positive electrode active material show a rapid structural change when the overcharged battery is heated at 200 to 270 ° C. After that, oxygen in the lattice is released due to such a structural change, and an unstable crystal structure is exhibited due to delithiumization during charging. That is, the commercialized lithium secondary battery has a disadvantage that it is very poor in heat.

In order to improve this, studies have been attempted to replace a part of nickel with a transition metal element to further raise the heat generation start temperature, or to prevent sudden heat generation. _{The LiNi 1-x} Co _x O ₂ (x = 0.1 to 0.3) material in which a part of nickel is replaced with cobalt shows excellent charge / discharge characteristics and life characteristics, but there is a problem of thermal safety. Could not be resolved. Further, a Li-Ni-Mn-based composite oxide in which manganese is partially substituted instead of nickel, or a Li-Ni-Mn-Co-based composite oxide in which nickel is substituted with manganese and cobalt, and technologies related to their production. Has also been developed in large numbers. In this regard, Patent No. 3890185 discloses a positive electrode active material of a new concept of forming a solid solution by uniformly dispersing manganese and a nickel compound at the atomic level, rather than the concept of partially substituting a transition metal with _{LiNiO 2} or LiMnO _2. doing. Further, European Patent No. 0918041 and US Patent No. 6,040,090 disclose Li-Ni-Mn-Co-based composite oxides in which nickel is replaced with manganese and cobalt, which are disclosed in the above documents. Although the thermal safety was improved as compared with the material in which the composite oxide was composed only of nickel and cobalt, the thermal safety of the nickel-based compound could not be completely solved.

In order to solve such a problem, a method has been proposed in which the surface composition of the positive electrode active material in contact with the electrolyte is changed by using a method such as coating the surface. The amount of coating for coating the positive electrode active material is generally 1 to 2% by weight or less less than that of the positive electrode active material. A small amount of coating substance forms an extremely thin thin film layer of about several nanometers to suppress side reactions with the electrolytic solution, or after coating, a solid solution is formed on the surface of the particles by heat treatment at a high temperature to form a solid solution inside the particles. Have a different metal composition from. At this time, the particle surface layer bonded to the coating substance is thin to several tens of nanometers or less, and due to the rapid composition difference between the coating layer and the particle bulk, the effect can be obtained if the battery is used for a long period of several hundred cycles. Decrease. Further, there is a problem that the effect of the battery is reduced due to an incomplete coating in which the coating layer is not evenly distributed on the surface.

In this regard, Korean Patent Publication No. 10-2005-0083869 discloses a lithium transition metal oxide having a concentration gradient of metal composition. However, although the oxides synthesized in the above literature have different metal compositions of the inner layer and the outer layer, the metal composition of the produced positive electrode active material does not gradually change. This can be solved through a heat treatment process, but at a high temperature of 850 ° C. or higher, there is almost no difference in concentration gradient due to thermal diffusion of metal ions or the like.

Patent No. 3890185 European Patent No. 0918041 U.S. Pat. No. 6,040,090 Republic of Korea Published Patent Publication No. 10-2005-0083869

An object of the present invention is to provide a new compound in which the Mn compound exhibits a concentration gradient in the primary particles and the secondary particles, and a method for producing the same, in order to solve the above-mentioned problems of the prior art.

In order to solve the above problems, the present invention contains secondary particles in which a plurality of primary particles are aggregated, and the positive electrode activity for a secondary battery contains lithium manganese oxide on the surface of the primary particles. Provide the substance.

The positive electrode active material for a secondary battery according to the present invention is characterized by containing a lithium manganese oxide between the primary particles inside the secondary particles. The positive electrode active material for a secondary battery according to the present invention is characterized in that the boundary surface (boundary) between the primary particles constituting the secondary particles also contains a lithium manganese oxide.

The positive electrode active material for a secondary battery according to the present invention is characterized in that the Mn concentration on the surface portion of the primary particles is higher than the Mn concentration inside the primary particles.

In the positive electrode active material for a secondary battery according to the present invention, the primary particles are characterized in that the Mn concentration has a gradient from the central portion to the surface portion of the primary particles.

In the positive electrode active material for a secondary battery according to the present invention, the lithium manganese _{oxide, Li 2 MnO 3, LiMn 2} O 4, MnO 2, Li w Mn 2 O 4 (0 <w <1), and Li ₂ It is characterized in that it is selected from the group consisting of MnO _{3 (1-v)} LiMn ₂ O _{4 (0 <v <1).} The positive electrode active material for a secondary battery according to the present invention is a process of producing an active material containing no Mn and then washing with water with a solution containing manganese. Manganese becomes present at the boundary of the primary particles in the secondary particles, and then lithium manganese oxide is formed while the manganese is oxidized in the plastic process. Positive electrode active material for a secondary battery according to the present invention, _Li 2 _MnO 3 by coupling ratio between manganese and _{oxygen, LiMn 2 O 4, MnO 2} , Li w Mn 2 O 4 (0 <w <1), and Li ₂ MnO _{3 (1-v)} Lithium manganese oxide selected from the group consisting of LiMn ₂ O ₄ (0 <v <1) is formed.

In the positive electrode active material for a secondary battery according to the present invention, the positive electrode active material is (020), (003), (101), (006), (102), (104), (005) at the time of XRD analysis. , (009), (107), (018), (110), and (113).

The positive electrode active material for a secondary battery according to the present invention is characterized in that a (020) peak due to _{Li 2} MnO _{3 appears between 2θ = 20 ° and 21 ° during XRD analysis.}

In the positive electrode active material for a secondary battery according to the present invention, a peak _{of Li 1-x} Mn ₂ O ₄ appears between 2θ = 36 to 38 °, 44 to 45 °, and 65 to 66 ° at the time of XRD analysis. It is characterized by.

The positive electrode active material for a secondary battery according to the present invention is characterized in that the peak intensity increase rate at the position (104) is 3% or less during the XRD analysis after charging as compared with the XRD analysis before charging.

The positive electrode active material for a secondary battery according to the present invention is characterized by including a lithium ion transfer path arranged in the central direction of the secondary particles in the primary particles.

The positive electrode active material for a secondary battery according to the present invention is characterized in that the lithium manganese oxide appears within 1 μm from the surface of the secondary particles.

The positive electrode active material for a secondary battery according to the present invention is characterized by being represented by the following chemical formula 1.

(In the above chemical formula 1, 0 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.02, 0 ≦ z ≦ 0.0006, 0 ≦ a ≦ 0.1, 0 ≦ b ≦ 0.1.
M1 is one or more selected from Al, Ni, Mn, Cr, Fe, Mg, Sr, V, Zn, W, Zr, B, Ba, Sc, Cu, Ti, Co, rare earth elements, and combinations thereof. It is an element of. )
The present invention further provides a secondary battery containing a positive electrode active material for a secondary battery according to the present invention.

The present invention further
The first step in producing precursors containing nickel and cobalt,
The second step of adding a lithium compound and an aluminum compound to the precursor and heat-treating the precursor to produce a composite metal compound, and
Provided is a method for producing a positive electrode active material for a secondary battery, which comprises a third step of washing the produced composite metal compound with a solution containing manganese and drying it.

In the positive electrode active material for a secondary battery according to the present invention, lithium manganese oxide is present in the periphery of the primary particles, and the lithium manganese oxide shows a concentration gradient from the center of the particles to the surface of the particles inside the secondary particles. The secondary battery containing the positive electrode active material for a secondary battery according to the present invention exhibits high capacity, high output, and high safety.

The result of measuring the metal concentration EDX of the positive electrode active material of the secondary battery manufactured by one Example of this invention is shown. The result of measuring the metal concentration EDX of the positive electrode active material of the secondary battery manufactured by one Example of this invention is shown. The result of measuring the metal concentration from the particle surface toward the center with respect to the positive electrode active material for a secondary battery which concerns on one Example of this invention is shown. The result of measuring the metal concentration from the particle surface toward the center with respect to the positive electrode active material for a secondary battery which concerns on one Example of this invention is shown. The results of measuring the metal concentration on the surface of the secondary particles from the boundary between the primary particles to the inside of the primary particles with respect to the positive electrode active material for the secondary battery according to the embodiment of the present invention are shown. The results of measuring the metal concentration on the surface of the secondary particles from the boundary between the primary particles to the inside of the primary particles with respect to the positive electrode active material for the secondary battery according to the embodiment of the present invention are shown. The result of XRD measurement with respect to the positive electrode active material for a secondary battery which concerns on one Example of this invention is shown. The result of XRD measurement with respect to the positive electrode active material for a secondary battery which concerns on one Example of this invention is shown. It is a drawing as a result of confirming the diffusion path of lithium ions existing at various positions of primary particles with respect to the positive electrode active material for a secondary battery which concerns on one Example of this invention. It is a result graph which confirmed the initial capacity of the battery manufactured using the positive electrode active material for a secondary battery which concerns on one Example of this invention. It is a result graph which confirmed the life of the battery manufactured using the positive electrode active material for a secondary battery which concerns on one Example of this invention at room temperature (25 ° C.) (A) or high temperature (45 ° C.) (B). The characteristics of a battery manufactured using the positive electrode active material for a secondary battery according to an embodiment of the present invention were confirmed after being charged and discharged once (A) or 50 times (B) at room temperature (25 ° C.). It is a result graph. The characteristics of a battery manufactured using the positive electrode active material for a secondary battery according to an embodiment of the present invention were confirmed after being charged and discharged once (A) or 50 times (B) at room temperature (25 ° C.). It is a result graph. The results of measuring the XRD of the positive electrode active material for a secondary battery before and after 50 times charging / discharging according to one example and the comparative example of the present invention are shown. The schematic diagram which cation migration occurs by charge / discharge in a layered secondary battery is shown. It is a result graph which confirmed XPS before and after charging and discharging 50 times of the secondary battery containing the positive electrode active material for a secondary battery by one Example (A) and comparative example (B) of this invention. The result of measuring Li-F in the particle before and after 50 times charge and discharge of the positive electrode active material for a secondary battery which concerns on one Example of this invention is shown.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are for exemplifying the present invention, and the present invention is not limited thereto. Anything having substantially the same configuration as the technical idea described in the claims of the present invention and having the same action and effect is included in the technical scope of the present invention.

Example 1. Production of Lithium Composite Oxide _{A precursor represented by Ni 0.98} Co _0.02 (OH) ₂ was produced by a coprecipitation reaction. The Al ₂ O ₃ was 1.4 mol added as LiOH and aluminum compound as the lithium compound to the prepared precursor, to prepare a positive active material for lithium secondary batteries and heat-treated.

The produced composite metal compound was washed with water using a water washing solution containing 0.01 mol% Mn.
Drying under the conditions of 150 ° C. and 400 _mmHg for 5 hours produced a secondary battery positive electrode active material represented by _{Li 1.01} Ni _0.913 Co _0.07 Al _0.014 Mn 0.000102.

Example 2.
_{Li 1.01} Ni _0.912 Co _0.07 Al under the same conditions and methods as in Example 1 except that the produced composite metal compound was washed with water using a water washing solution containing 0.02 mol% Mn. _A secondary battery positive electrode active material represented by the chemical formula of 0.014 Mn _{0.000202 was produced.}

Example 3.
_{Li 1.01} Ni _0.911 Co _0.07 Al under the same conditions and methods as in Example 1 except that the produced composite metal compound was washed with water using a water washing solution containing 0.03 mol% Mn. _A secondary battery positive electrode active material represented by the chemical formula of 0.014 Mn _{0.000302 was produced.}

Example 4.
_{Li 1.01} Ni _0.91 Co _0.07 Al under the same conditions and methods as in Example 1 except that the produced composite metal compound was washed with water using a water washing solution containing 0.04 mol% Mn. _A secondary battery positive electrode active material represented by the chemical formula of 0.014 Mn _{0.000402 was produced.}

Example 5.
_{Li 1.01} Ni _0.909 Co _0.07 Al under the same conditions and methods as in Example 1 except that the produced composite metal compound was washed with water using a water washing solution containing 0.05 mol% Mn. _A secondary battery positive electrode active material represented by the chemical formula of 0.014 Mn _{0.000502 was produced.}

Example 6.
_{Li 1.01} Ni _0.908 Co _0.07 Al under the same conditions and methods as in Example 1 except that the produced composite metal compound was washed with water using a water washing solution containing 0.06 mol% Mn. _A secondary battery positive electrode active material represented by the chemical formula of 0.014 Mn _{0.00602 was produced.}

Comparative example 1. _{Production of Lithium Composite Oxide Not Washed with Manganese Li 1.01} Ni _0.914 Co _0.07 Al _{0 under the} same conditions and methods as in Example 1 except that it is immersed in a manganese-containing solution and washed with water. A lithium composite oxide represented by the _.014 O _{2 chemical formula was produced.}

<Experimental Example> EDX measurement EDX was measured at different measurement ratios with respect to the positive electrode active material produced in the above example, and the results are shown in FIGS. 1 and 2.

In the case of the positive electrode active material of the present invention washed with water in the Mn-containing solution in FIG. 1, Mn is present on the surface of the secondary particles, and is present on the surface of the secondary particles in FIG. It can be confirmed that Mn also exists at the boundary between the next particles.

<Experimental Example> Measurement of Metal Concentration Inside Particles The changes in the concentrations of manganese, cobalt, nickel, and aluminum in the positive electrode active material of the secondary battery of Example 4 were confirmed from the surface of the secondary particles toward the center from the TEM measurement results. The results are shown in FIG.

In FIG. 3, it can be confirmed that manganese is mainly located within 1 μm of the surface of the secondary particles, the maximum concentration is 5% by weight or less, and the concentration gradient decreases from the surface toward the center.

The weight% and atomic% of manganese, cobalt, nickel, and aluminum in the TEM measurement range were measured and shown in Table 2 and FIG. 4 below.

<Experimental Example> Confirmation of Mn Concentration Gradient The changes in the concentrations of nickel, cobalt, aluminum, and Mn contained in the positive electrode active material of the secondary battery of Example 4 are measured on the surface of the secondary particles (surface, line data 2) and inside the secondary particles. The measurement was performed at the portion in contact with the boundary between the primary particles (grain boundary, line data 6), and the results are shown in FIGS. 5 and 6. FIG. 6 shows an expanded result of measuring the concentration gradient from the surface of the secondary particle to the inside of the particle in FIG.

In FIGS. 5 and 6, the concentration gradient was shown while the Mn concentration decreased from the surface of the secondary particles toward the center, manganese was located within 1 μm on the surface of the secondary particles, and manganese was not detected inside.

As shown in FIG. 5, Mn is detected at the boundary between the primary particles located on the surface and inside of the secondary particles, that is, in the grain boundary, and Mn is not detected inside the primary particles, but inside the primary particles. A concentration gradient was observed in which the concentration of Mn decreased in the direction.
<Experimental Example> XRD measurement XRD was measured for the positive electrode active material produced in the above Examples and Comparative Examples, and the results are shown in FIGS. 7 and 8.

In the case of the positive electrode active material of the present invention treated with the Mn-containing solution according to the embodiment of the present invention in FIG. 7, at the time of XRD analysis, (020), (003), (101), (006), (102), ( It can be confirmed that the peaks are represented at the positions 104), (005), (009), (107), (018), (110), and (113).

In FIG. 8, in the case of the positive electrode active material of the present invention, the (020) peak due to Li2MnO3 between 2θ = 20 ° and 21 °, and Li _{1-x between 2θ = 36 to 38 °, 44 to 45 ° and 65 to 66 °.} It was confirmed that the peak of Mn ₂ O _{4 appeared.} That is, in the positive electrode active material coated with the manganese-containing solution according to the present invention, the lithium manganese oxide exists in a spinel structure of _{Li 2} MnO ₃ and Li _1-x Mn ₂ O ₄ different from the crystal structure of the positive electrode active material. I was able to confirm that it would be done.

<Experimental Example> Confirmation of Lithium Ion Movement Path The diffusion path of lithium ions was confirmed by TEM measurement data according to each position of the primary particles of the positive electrode active material of the secondary battery of Example 4, and is shown in FIG. In FIG. 9, A indicates the surface position of the secondary particle, B indicates the central position of the primary particle, and C indicates the boundary between the primary particles in the secondary particle.

In FIG. 9, the lithium ion diffusion path is clearly present at the B position inside the particle, and the lithium ion diffusion path is at the A position, which is the surface position of the secondary particle, and the C position, which is the boundary between the primary particles in the secondary particle. It was confirmed that the crystal structure was distorted.

<Experimental Example> Measurement of Residual Lithium Residual lithium of the positive electrode active material produced in Examples 1 to 6 and the positive electrode active material produced in Comparative Example was measured.

Specifically, 1 g of the lithium composite oxide was immersed in 5 g of distilled water and then stirred for 5 minutes. After the stirring was completed, this was filtered to obtain a filtrate, to which a 0.1 M HCl solution was added and titrated to pH 5. At this time, the volume of the added HCl solution was measured and the results of analyzing the residual lithium of the positive electrode active material of the secondary battery used were shown in Table 3 below.

<Manufacturing Example> Manufacture of Battery A battery was manufactured using the positive electrode active material of the secondary battery manufactured in Examples 1 to 6 and the positive electrode active material manufactured in Comparative Example 1.

First, a slurry was produced by mixing a secondary battery positive electrode active material, super-P as a conductive material, and polyvinylidene fluoride (PVdF) as a binder at a weight ratio of 95: 5: 3. The produced slurry was uniformly applied to an aluminum foil having a thickness of 15 μm, and this was vacuum dried at 135 ° C. to produce a positive electrode for a lithium secondary battery.

The acquired positive electrode for a lithium secondary battery, lithium foil as a mating electrode, a porous polyethylene film (Celgard LLC., Celgard 2300) having a thickness of 25 μm as a separator, and LiPF ₆ having a concentration of 1.15 M as a liquid electrolyte are included. A coin battery was manufactured using a solvent in which ethylene carbonate and ethyl methyl carbonate were mixed in a volume ratio of 3: 7.
<Experimental Example> Battery Characteristic Measurement-Capacity Characteristics The initial capacity of the battery containing the positive electrode active material of the present invention and the positive electrode active material of the comparative example manufactured in the above production example was measured, and the results are shown in FIGS. 10 and 4. It was.

As shown in FIG. 10 and Table 4, the battery manufactured by using the positive electrode active material of the secondary battery according to the present invention was excellent in charge / discharge efficiency.
<Experimental Example> Battery Characteristic Measurement-Lifetime Characteristics The lifespan characteristics of the coin battery were measured at room temperature (25 ° C.) and high temperature (45 ° C.), and the results are shown in FIGS. 11 and 5.

As shown in FIG. 11 and Table 5, the battery manufactured by using the secondary battery positive electrode active material according to the present invention has improved life characteristics as compared with the battery of Comparative Example 1. In particular, the batteries produced by using the positive electrode active materials of the secondary batteries of Examples 2 to 4 are excellent in the effect of maintaining the life of the batteries not only at room temperature but also at high temperatures.

<Experimental example> Battery characteristic measurement-High temperature charge / discharge characteristics The charge / discharge characteristics when a coin battery is charged / discharged once or 50 times are measured at room temperature (25 ° C) and high temperature (45 ° C), and the results are dQ / dV. Converted to voltage (V) and shown in FIGS. 12 and 13.

As shown in FIGS. 12 and 13, a battery manufactured by using the positive electrode active material of the secondary battery according to the present invention has excellent charge / discharge characteristics not only at room temperature but also at high temperature.

<Experimental Example> XRD measurement after charging / discharging With respect to a coin battery manufactured using the positive electrode active material manufactured in the above Examples and Comparative Examples, the battery was disassembled after charging / discharging 50 times, and the obtained positive electrode was obtained. The XRD was measured for the active material and compared with the XRD data measured for the active material before the battery was manufactured, and the results are shown in FIGS. 14 and 6.

As shown in FIGS. 14 and 6, the coin battery manufactured by using the secondary battery positive electrode active material of Example 4 in the present invention has a change of 5% or less in I (104) value even after 50 times of charging and discharging. It was less than the comparative example.
In the case of a general battery, if charging and discharging are continued, the crystal structure is deteriorated by cation migration. As shown in FIG. 15, it could be determined that the peak intensity at the position (104) represents the degree to which cation migration occurred.
In the case of the positive electrode active material of the present invention, the increase in the I (104) value is only 2.61% even after the charging / discharging is continued, and the degree of deterioration of the bulk structure is reduced even after the charging / discharging. It was confirmed that it would be done.

<Experimental Example> Confirmation of XPS of Battery A coin battery manufactured using the secondary battery positive electrode active material of Example 4 in Production Example 1 and a secondary battery positive electrode active material manufactured in Comparative Example 1 were used. The XPS of the coin battery before and after charging and discharging 50 times was measured, and the results are shown in FIGS. 16, 17, and 7.

In FIGS. 16 and 7, the coin battery manufactured by using the secondary battery positive electrode active material of Example 4 according to the present invention is still in I (Li-F), that is, Li-F even after being charged and discharged 50 times. The intensity of the peak decreased.

<Experimental Example> Measurement of LiF generation inside the positive electrode active material In Production Example 1, a coin battery manufactured using the secondary battery positive electrode active material of Example 4 and a secondary battery positive electrode active material manufactured in Comparative Example 1 were used. After charging and discharging the coin battery manufactured in the above 50 times, the cross section of the positive electrode active material was measured by EDX, and the result is shown in FIG.

In FIG. 17, it was confirmed that in the case of the positive electrode active material of the present invention, less Li-F inside the particles was detected than in the comparative example.

Claims (12)

Containing secondary particles in which a plurality of primary particles are aggregated,
The surface of the primary particles contains lithium manganese oxide.
Lithium manganese oxide is contained between the primary particles inside the secondary particles,
The Mn concentration on the surface of the primary particles is higher than the Mn concentration inside the primary particles.
The lithium manganese oxide, viewed contains a lithium manganese oxide having a spinel crystal structure,
The lithium manganese oxide on the surface of the primary particles is a positive electrode active material for a secondary battery , which contains a lithium manganese oxide having no spinel crystal structure and a lithium manganese oxide having a spinel crystal structure. The positive electrode active material for a secondary battery according to claim 1, wherein the primary particles have a gradient in Mn concentration from the central portion to the surface portion of the primary particles. The positive electrode active material for a secondary battery according to claim 1, wherein the lithium manganese oxide appears within 1 μm from the surface of the secondary particles. The positive electrode active material was prepared as (020), (003), (101), (006), (102), (104), (005), (009), (107), (018), at the time of XRD analysis. The positive electrode active material for a secondary battery according to claim 1, which represents a peak at the positions (110) and (113). The positive electrode active material for a secondary battery according to claim 1, wherein the (020) peak due to _{Li 2} MnO ₃ appears between 2θ = 20 ° and 21 ° during XRD analysis. The secondary according to claim 1, _{wherein the positive electrode active material shows a peak of Li 1-x} Mn ₂ O ₄ between 2θ = 36 to 38 °, 44 to 45 °, and 65 to 66 ° at the time of XRD analysis. Positive electrode active material for batteries. The positive electrode active material for a secondary battery according to claim 1, wherein the positive electrode active material has a peak intensity increase rate of 3% or less at the position (104) during the XRD analysis after charging as compared with the XRD analysis before charging. .. The positive electrode active material for a secondary battery according to claim 1, wherein the positive electrode active material includes a lithium ion transfer path arranged in the primary particles in the central direction of the secondary particles. The secondary particles are the positive electrode active material for a secondary battery according to claim 1, which is represented by the following chemical formula 1.

(In the above chemical formula 1, 0 ≦ x ≦ 0.1, 0 ≦ y ≦ 0.02, 0 < z ≦ 0.0006, 0 ≦ a ≦ 0.1, 0 ≦ b ≦ 0.1.
M1 is one or more selected from Al, Ni, Mn, Cr, Fe, Mg, Sr, V, Zn, W, Zr, B, Ba, Sc, Cu, Ti, Co, rare earth elements, and combinations thereof. It is an element of. ) A secondary battery containing the positive electrode active material for a secondary battery according to claim 1. The first step in producing precursors containing nickel and cobalt,
The second step of adding a lithium compound to the precursor and heat-treating it to produce a composite metal compound,
The third step of washing the produced composite metal compound with a solution containing manganese and drying it,
The method for producing a positive electrode active material for a secondary battery according to claim 1. The method according to claim 11, wherein the second step comprises adding an aluminum compound in addition to the lithium compound to the precursor and performing a heat treatment to produce the composite metal compound.

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